PREPARATION OF A MICROELECTRODE ARRAY USING DESORPTION OF A SELF-ASSEMBLED MONOLAYER OF HEXADECYLTHIOLATE ON A GOLD ELECTRODE IN CYANIDE SOLUTION

The immersion of an Au electrode coated with a self-assembled monolaye r of hexadecylthiolate (HDT\Au) in KCN aqueous solution causes desorpt ion of chemisorbed hexadecylthiolate molecules which depends on the im mersion time. The desorption is initiated at pinholes of the HDT\Au el ectrode through which cyanide ions reach the gold substrate, causing d esorption of the adsorbed hexadecylthiolate. Electrochemical depositio n of copper onto the HDT\Au electrode after immersing the electrode in KCN solution revealed that the size of holes generated by desorption of the adsorbed hexadecylthiolate became large as the immersion time i n the KCN solution increased, and the holes produced were distributed fairly homogeneously over the entire surface of the HDT\Au electrode. Detailed simulations of cyclic voltammograms of the HDT\Au electrode o btained in K-4[Fe(CN)(6)] solutions after immersing the electrode in t he KCN solution suggested that the HDT\Au electrodes achieved electroc hemical activities characteristics of a microelectrode array with this immersion in the cyanide solution. The average radius of the microele ctrodes estimated by the best fitting of the experimentally obtained v oltammograms to the simulated ones accorded well with that obtained fr om the observations of the Cu-deposited electrode. (C) 1997 Elsevier S cience S.A.